Assay module transport apparatus for use in an automated analytical instrument

ABSTRACT

An automated analytical instrument for conducting assays for components of interest in fluid samples. The instrument includes a rotably mounted supply unit or segment adapted to hold a plurality of foil-sealed magazines containing assay modules, a testing system for assaying a fluid sample for a component of interest using an assay module, an assay module transport assembly for transporting an assay module from a magazine in the supply unit to the testing system, and a microprocessor for controlling the operation of the automated analytical instrument. In one embodiment, the assay module transport assembly includes a cutter assembly for cutting away a layer of material such as a thin foil layer covering a desired assay module within the magazine, an assay module receiving platform disposed in front of the magazine, an assay module ejector mechanism for pushing an assay module from the magazine onto the assay module receiving platform, and an assay module transfer mechanism for moving the assay module from the assay module receiving platform to the testing system. The cutter assembly and the assay module receiving platform are movable vertically on a first elevator assembly, and the assay module ejector assembly is movable vertically on a second elevator assembly.

BACKGROUND OF THE INVENTION

The present invention relates generally to automated analyticalinstruments and more particularly to automated analytical instrumentsfor use in conducting assays for components of interest in fluidsamples.

In recent years, a number of automated instruments have been developedto perform analyses of fluid samples. As is known in the art, suchinstruments may be used to test various types of biological fluids forsubstances of interest, for example, to find evidence of disease, tomonitor therapeutic drug levels, and the like. Typically, such automatedanalytical instruments utilize either liquid reagents or dry reagents toassay for a substance of interest. Various different types of assaydevices are known for use in such automated instruments including, forexample, dry thin-film multilayer assay elements which are typicallymounted in an assay module and capillary assay devices.

Generally speaking, the testing system portion of automated analyticalinstruments which use assay modules to test for a component of interesttypically include a fluid dispensing system for metering out a quantityof the fluid sample to be analyzed to an assay module, a temperaturecontrolled chamber for holding the assay modules at the appropriatetemperature to allow the reaction to take place, an analyzing system formeasuring a detectable change brought about by the presence of thesubstance of interest in the fluid sample and some mechanism forconveying the assay module to each of the foregoing components in theproper order.

The assay modules may be provided by various techniques. In one type ofautomated analytical instrument an assay module to be used is manuallyloaded into an assay module transfer device. The assay module is thentransferred to the test system. In U.S. Pat. No. 4,152,390, there isdescribed an automated analytical instrument which includes, in additionto the testing system, a supply unit for holding a plurality of assaymodules and a transfer apparatus for transferring an assay module fromthe supply unit to the testing system. The assay modules are stacked incontainers, which may be received in a nest of the analyzing apparatuswith a spring biased plunger arranged to enter the container through anopening. The plunger engages a movable element located in the containerbehind the stack of modules to urge the top module forwardly towards thetesting system portion of the instrument. The transfer apparatuscomprises a bell crank pivotally mounted to a frame member and having afirst leg which is connected to a pusher member through a link. Thepusher member is mounted for reciprocating movement in a bearing blockcarried on a cover member. A second leg of the bell crank is pinned to aconnecting rod which transmits power to the bell crank. The rod isadapted to pivot the bell crank through a limited arc which in turncauses the pusher member to reciprocate in and out of the cartridge. Asthe pusher member moves into the cartridge, it engages a slide and movesit from the cartridge into a metering position directly under themetering tip.

In copending, commonly assigned United States patent application Ser.No. 732,053 filed on Jul. 18, 1991 in the name of Robert C. Maclndoe,Jr., there is disclosed an example of an automated analytical instrumentof the type which uses assay modules to perform assays for components ofinterest in fluid samples. The instrument includes a fluid sample cupholder having a plurality of fluid sample holding cups, a supplyapparatus for holding a supply of assay modules, a testing system whichincludes apparatus for testing the fluid sample using the assay modules,and an assay module transfer apparatus for transferring an assay moduleto be used from the supply apparatus to the testing system. The assaymodule transfer apparatus includes an assay module transfer unit whichis mounted on a supporting structure and is movable vertically. Theassay module transfer unit includes a mechanism for pulling an assaymodule out from the supply apparatus and a mechanism for pushing theassay module so obtained into the testing system. By moving the assaymodule transfer unit vertically, the assay module transfer unit can bealigned with assay modules disposed at different vertical locationswithin the supply apparatus.

As can readily be appreciated, automated analytical instruments whichinclude an automated mechanism for transporting assay modules storedwithin the instrument to the testing system are desirable since they donot require an operator to manually feed assay modules, one at a time,into the testing system. As the state of the art with respect toautomated analytical instruments advances there is a continuing desirefor improved mechanisms for use therein including new and improved assaymodule transport mechanisms for transporting assay modules from an assaymodule supply apparatus to the test system.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and improvedautomated analytical instrument.

It is another object of this invention to provide an automatedanalytical instrument which includes a novel assembly for transportingan assay module from an assay module supply apparatus to the testingsystem of the instrument.

It is still object of this invention to provide an automated analyticalinstrument using assay modules wherein the assay modules are stored foruse in magazines which are subdivided to form compartments, eachcompartment being adapted to hold a single assay module.

Yet another object of the invention is to provide a novel cutterassembly for use with the assay module transport apparatus of theinvention.

Additional objects, as well as further features and advantages, of thepresent invention will be set forth in part in the description whichfollows, and in part will be obvious from the description or may belearned by practice of the invention. The objects, features, andadvantages of the present invention may be realized and attained bymeans of the instrumentalities and combinations pointed out in theappended claims.

Accordingly, to achieve the foregoing objects and in accordance with thepurpose of the present invention as broadly set forth and embodiedherein, an automated analytical instrument for use in conducting assaysfor a component of interest in a fluid sample is provided. Theinstrument includes an assay module supply apparatus which is adapted tohold a supply of assay modules which are specific for a component orcomponents of interest, a testing system for assaying a fluid sample fora component of interest using an assay module, an assay module transportapparatus for transporting an assay module from said assay module supplyapparatus to the testing system, and a microprocessor for controllingthe operations of said automated analytical instrument. The assay moduletransport assembly includes an assay module receiving platform disposedproximate to said assay module supply apparatus, an assay module ejectormechanism for pushing an assay module from said assay module supplyapparatus onto said assay module receiving platform, and a mechanism formoving an assay module from said assay module receiving platform to saidtesting system.

In a preferred embodiment of the invention, the assay module ejectormechanism and the assay module receiving platform of the assay moduletransport apparatus are movable vertically so that assay modulesdisposed at different vertical levels within the assay modules supplyapparatus may be accessed. In another preferred embodiment of theinvention, the assay module supply unit is loaded with sealed magazinescontaining a plurality of assay modules, the openings in the magazinesbeing sealed with a thin layer of material such as a foil, and the assaymodule transport assembly further includes a cutter adapted to tear awaythe material disposed in front of an assay module in the magazine, thecutter also preferably being movable vertically.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are hereby incorporated into andconstitute a part of this specification, illustrate the preferredembodiments of the invention and, together with the description, serveto explain the principles of the invention. In these drawings whereinlike reference numerals represent like parts:

FIG. 1 is a simplified perspective view of an automated analyticalinstrument constructed according to the teachings of the presentinvention;

FIG. 2 is a perspective view of a plurality of the containers forholding fluid samples for use with the automated analytical instrumentshown in FIG. 1;

FIG. 3 is a simplified perspective view taken from the front right ofthe fluid sample holding tray transport assembly shown in FIG. 1;

FIG. 4 is a perspective view taken from the top of one of the fluidsample holding trays shown in FIG. 1;

FIG. 5 is a bottom view of the fluid sample holding tray shown in FIG.1;

FIG. 6 is a fragmentary perspective view taken from the left of thesample tray loading unit shown in FIG. 2;

FIG. 6(a) is a top view of the loading tray shown in FIG. 6;

FIG. 7 is a front view showing a fluid sample holding tray seated on thetray loading unit in FIG. 1;

FIG. 8 is an end view showing the carriage in the transport assembly inFIG. 3 in engagement with a fluid sample holding tray in FIG. 4;

FIG. 9 is a simplified perspective view of those components of theautomated analytical instrument of FIG. 1 that pertain to the assaymodule transport assembly, certain elements of the assay moduletransport assembly being shown in block form for simplicity and clarity;

FIG. 10 is a partially exploded perspective view of one of the supplyunits or segments of the assay module supply apparatus shown in FIG. 1with a plurality of magazines mounted therein;

FIG. 11 is an enlarged front view, broken away in part, of one of themagazines shown in FIG. 10;

FIG. 12 is a rear perspective view, broken away in part, of the magazineshown in FIG. 11;

FIG. 13 is an enlarged perspective view of one of the assay modulesshown in FIG. 11;

FIG. 14 is an enlarged front perspective view of the assay moduleejector mechanism shown in FIG. 9;

FIG. 15 is an enlarge top view of the assay module receiving platformshown in FIG. 9;

FIG. 16 is an enlarged front view of the cutter assembly shown in FIG.9;

FIG. 17 is a left side view of the cutter assembly shown in FIG. 16;

FIG. 18 is a right side view of the cutter assembly shown in FIG. 16;

FIG. 19 is an enlarged perspective view of the assay module transportmechanism shown in FIG. 9;

FIG. 20 is a perspective view of the assay module loader assembly shownin FIG. 19; and

FIG. 21 is a front view of the loader arm shown in FIG. 20.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIG. 1, there is shown an automated analyticalinstrument constructed according to the teachings of the presentinvention for conducting assays for components of interest in fluidsamples, the instrument being identified by reference numeral 15.Portions of instrument 15 not pertinent to this invention are neithershown nor discussed.

Instrument 15 includes an assay module supply apparatus 17 for storing aplurality of unused assay modules each containing one or more reagentsuseful in the detection of a particular component in a fluid sample.Instrument 15 also includes a temperature controlled chamber 21 whereinthe testing of fluid samples occurs in the manner hereinafter describedand an assay module transport assembly 23 for transporting assay modulesone at a time, from supply apparatus 17 onto a rotatably mountedturntable 24 disposed within chamber 21. Instrument 15 further includesa pair of pipette assemblies 25-1 and 25-2 for dispensing quantities offluid samples to assay modules disposed at a pair of metering stations26 and 28 (shown schematically) located within chamber 21. In thepreferred embodiment illustrated in FIG. 1 the metering stations arelocated in proximity to turntable 24 and the assay modules are removedfrom the turntable and deposited at a metering station. Subsequent toreceiving the fluid samples the assay elements are returned to theturntable where they reside during the incubation period. It will beappreciated by those skilled in the art that the sample fluid may bedeposited on the assay elements prior to their insertion in thetemperature-controlled chamber 21 or when the assay elements are locatedon the turntable.

The instrument 15 additionally includes a plurality of, preferablythree, optical read stations (not shown) located within chamber 21 formeasuring a signal generated in the assay element which is a function ofthe concentration of a component of interest in the sample fluid. Theoptical read stations, as is the case with the metering stations 26 and28, are located in proximity to the turntable 24. Automated shuttlemechanisms (not shown) are used to transport assay modules back andforth between turntable 24 and metering stations 26 and 28 and back andforth between turntable 24 and an optical read station. Each of theoptical read stations has associated with it an optical read device, oneof which is shown at 27 for purposes of illustration. In the preferredembodiment illustrated in FIG. 1 the optical read devices are locatedoutside the temperature-controlled chamber 21 and read the signalsgenerated in the assay modules through an opening in the bottom wall ofthe chamber 21. Pipette assemblies 25 obtain pipette tips 28-1 from apipette tip holding container 28-2 suitably located within instrument15.

Instrument 15 also includes a fluid sample holding tray transportassembly 31 (FIG. 3) which serves to transport one or more fluid sampleholding trays 29 within instrument 15 as will hereinafter be discussed.Each fluid sample holding tray 29 is adapted to hold a plurality ofsample fluid containers 33. A plurality of sample fluid containers 33are shown in FIG. 2. Containers 33 can take the form of either cups ortubes. For illustrative purposes only, containers 33 are shown as tubes.

Instrument 15 additionally can include a diluent tray 34 for holdingdiluents and a diluent tray transport assembly 34-1. Transport assembly34-1 serves to transport diluent tray 34 to a desired location withininstrument 15. Transport assembly 34-1 includes a rail on which tray 34is mounted and a motor driven chain attached to tray 34 for moving tray34 on the rail.

Instrument 15 further includes a microprocessor (not shown) forcontrolling the operation of the various components within instrument15. It should be noted that when reference is made herein to amicroprocessor it is intended to include the overall controllingprocessing unit (CPU) as well as any number of embedded single chipcontrollers each of which is typically utilized to control the operationof one mechanism such as a stepper motor for driving various assembliesas will be described herein. Instrument 15 also preferably includes aCRT screen 35 which can be used to provide a visual display of the assayresults obtained from the analyses performed on the instrument. In apreferred embodiment, screen 35 is a touch screen which allows anoperator to input information and instructions to the instrument 15. Allof the components noted above are supported in a frame 36.

Fluid sample holding tray transport assembly 31, which is shownseparately in FIG. 3, includes a conveyor 37 for moving fluid sampleholding trays 29 along a path past pipette assemblies 25, a sampleholding tray loading unit 39 for automatically loading fluid sampleholding trays 29 onto conveyor 37 and a sample holding tray unloadingunit 41 for automatically unloading fluid sample holding trays fromconveyor 37.

In FIG. 1, two fluid sample holding trays 29 are shown, one at sampletray loading unit 39 and the other at sample tray unloading unit 41;however, it should be understood that the number of fluid sample holdingtrays 29 shown in FIG. 1 and their locations within instrument 15 arefor illustrative purposes only.

In the operation of instrument 15, fluid samples to be tested aredeposited in fluid sample containers 33. Containers 33 are then loadedonto trays 29. Alternatively, containers 33 could be filled after theyare loaded into trays 29. One or more trays 29 are then placed by theoperator on loading unit 39, the number of trays 29 placed thereondepending on the number of fluid samples to be tested and the number oftrays 29 that can actually fit on loading unit 39. At the same time,each pipette assembly 25 takes a tip 25-1 from a holding container 28-2.Trays 29 are placed on loading unit 39 in a row, one behind the other.In loading unit 39, the first tray 29 in the row is automaticallyadvanced to the tray loading area at the rear of loading unit 39, loadedonto conveyor 37 and then moved by conveyor 37 to a predetermined one ofthe pipette assemblies 25. After quantities of the desired fluid sampleshave been aspirated from tray 29 by a pipette assembly, tray 29 is movedalong conveyor 37 to unloading unit 41 where it is unloaded fromconveyor 37. The next tray 29 in the row is then loaded from loadingunit 39 to conveyor 37 and so forth. The loading, moving, dispensing,and unloading operations are all controlled by the microprocessor.

A perspective view taken from the top of a fluid sample holding tray 29is shown in FIG. 4 and a bottom view of the fluid sample holding tray 29is shown in FIG. 5. Tray 29, as illustrated, can be molded polymericstructure which is shaped to include a top portion 42 having a pluralityof openings 43 in which can be removably mounted containers 33, left andright side flanges 45 and 46, respectively, having slots 47 and 48,respectively, and a bottom wall 49 which includes a longitudinal slot 50having a pair of integrally formed notches 51 and 53. Openings 43 areshaped and sized according to the shape of the containers 33 being used(i.e. cups or tubes).

Conveyor 37 includes a monorail 55 which extends from loading unit 39 tounloading unit 41 along a path which passes by the pipette assemblies25-1 and 25-2. A carriage 57 adapted to support a fluid sample holdingtray 29 is slidably mounted on monorail 55. Carriage 57 includes a pairof spring loaded detents 58 which are used to removably secure carriage57 to a tray 29 to be transported by carriage 57. Carriage 57 is fixedlysecured to a rotably mounted endless belt 59. Belt 59 is driven by areversible stepper motor 61, the operation of which is controlled by themicroprocessor. When motor 61 is energized, endless belt 59 will movecausing carriage 57 to slidably move along monorail 55, the direction ofmovement of carriage 57 on monorail 55 depending on the rotation of thedrive shaft of motor 61.

Loading unit 39, see especially FIGS. 6 and 6(a), is an elongated rigidstructure and includes a base 63 having front and rear lateral slots64-1 and 64-2, respectively, a pair of side walls 65 and 67 which extendupwardly on either side of base 63, a front area 69 and a rear area 71.Loading unit 39 is positioned with respect to conveyor 37 so that rearslot 64-2 is aligned with monorail 55. A pair of endless belts 73 and 75are rotably mounted on loading unit 39, one on each side thereof, andextend from the front area 69 of unit 39 to the rear area 71 of unit 39.Endless belts 73 and 75 are driven by a motor 77 which is coupled toboth belts. Belt 73 is disposed lower than belt 75 so as not tointerfere with the loading of a tray 29 onto carriage 57 as willhereinafter be explained. When a tray 29 is placed on loading unit 39,bottom wall 49 will be seated on belt 73 and side flange 46 will beseated on belt 75. Motor 77 is controlled by the microprocessor. Belts73 and 75 are used to carry tray 29 the to rear area 71 of unit 39 whereit is automatically transferred to carriage 57. An elongated detectorplate 79 extending from the front area 69 of unit 39 to the rear area 71of unit 39 is pivotally mounted on the inside surface of outer side wall67. A signal interrupter plate 81 is fixedly attached to detector plate79. A first sensor unit 83 is mounted on loading unit 39 in closeproximity to plate 81. For purposes of illustration sensor unit 83 isshown being mounted on the front area 69 of loading unit 39. It will beappreciated that the sensor unit 83 can be mounted at any suitablelocation along the side of loading unit 39. First sensor unit 83includes an LED 83-1 and a light detector 83-2. When there is no tray 29in loading unit 39, plate 79 is pivoted outward at an angle of about 30degrees, and detector 83-2 receives a light signal from LED 83-1 andsends an electrical signal to the microprocessor indicating that thelight signal is received. When a tray 29 is placed in loading unit 39 atany location along base 63, plate 79 will be pivoted up causing plate 81to interrupt the signal sent by first sensor unit 83 to themicroprocessor. This in turn will cause the microprocessor to activatemotor 77.

Unit 39 also includes a 45 degree movable plate 84 which is mounted onthe outside of side wall 67. Movable plate 84 is normally in a raisedposition. Movement of plate 84 is controlled by a solenoid 84-1. Plate84 serves two purposes, namely, to guide tray 29 as it is moved back inloading unit 39 to rear area 71 and to prevent tray 29 from moving outon monorail 55 until allowed to do so by the microprocessor. When a tray29 is placed in loading unit 39, plate 84 will extend up in slot 48 oftray 29. Plate 84 can also, where desired, be utilized to serve alatching function, e.g., to restrain tray 29 and prevent it from beingmoved accidently on the loading unit 39.

When tray 29 has been moved to the rear area 71 of loading unit 39 andis in position to receive and engage carriage 57 (i.e., bottom slot 50on tray 29 is aligned with rear slot 64-2 on the loading unit), a signalis sent by a second sensor (not shown), which is identical to sensor 83,to the microprocessor. This signal causes the microprocessor to send outa signal which stops motor 77, which drives belts 73 and 75, and asignal which starts motor 61, which moves carriage 57 on monorail 55 sothat it can slide into slot 50 in tray 29. As carriage 57 moves undertray 29, spring detents 58 on the top of carriage 57 engages the notches51 and 53 in tray 29, thereby releasably securing carriage 57 to tray29. An end view showing carriage 57 in engagement with tray 29 is shownin FIG. 8. As soon as carriage 57 engages tray 29, a signal is sent tothe microprocessor by a third sensor (not shown), which is alsoidentical to sensor 83. The signal from the third sensor to themicroprocessor causes it to send out a signal changing the direction ofrotation of motor 61 which moves belt 59. At the same time, themicroprocessor sends out a signal to solenoid 84-1 which causes plate 84to be lowered. These two signals from the microprocessor will enablecarriage 57 to move back out on monorail 55 carrying with it a tray 29.Carriage 57 will stop at a pipette assembly, 25-1 or 25-2, theparticular pipette assembly being controlled by the microprocessor.After all the fluid samples have been withdrawn from tray 29 foranalysis, carriage 57 will transport tray 29 to unloading unit 41.

Unloading unit 41 is similar in construction to loading unit 39 in thatit includes a base 91 having front and rear slots 92 and 93, side walls94 and 95, a pair of belts 96 and 97 driven by a motor (not shown), adetector plate 98 coupled to an interrupter plate (not shown) which issimilar to interrupter plate 81 of loading unit 39 (FIG. 6a), a 45degree movable latch plate 99 and a set of three sensors (not shown).However, detector plate 98 only extends forward a short distance fromthe rear of the unit. Latch plate 99 is in a normally raised position asis the case with movable plate 84. In order to allow tray 29 to be movedonto unload station 41, latch plate 99 must be lowered. Amicroprocessor-controlled solenoid (not shown) causes latch plate 99 tobe lowered. In the operation of unit 41, as soon as a tray 29 has beenbrought in, latch 99 will be raised, carriage 57 will move back outleaving tray 29 on unit 41 and belts 96 and 97 will move tray 29forward. As soon as tray 29 moves past plate 98, the motor will bestopped causing belts 96 and 97 to stop movement.

Referring now to FIG. 9, assay module supply apparatus 17, assay moduletransport assembly 23, and a portion of turntable 24 of chamber 21 areschematically shown and are hereinafter shown and described in detail toillustrate the operation of assay module transport assembly 23.

As can be seen, supply apparatus 17 comprises a cylindrically shapedframe 101, a rotatably mounted, annularly-shaped turntable 103 uponwhich frame 101 is supported, a stepper motor 105 which is coupled toturntable 103 through a belt (not shown) for rotating turntable 103, aplurality of arcuately shaped assay module supply units or segments 107(only one of which is shown in FIG. 9 for clarity) which are removablymounted on the outside of frame 101, and a plurality of magazines 109which are removably mounted in each segment 107. The operation anddirection of motor 105 and, hence, the rotational position of segments107 are controlled by the microprocessor.

As can be seen in greater detail in FIG. 10, each segment 107 has aplurality of generally rectangularly shaped chambers 111circumferentially spaced thereon in two sections. The back wall of eachchamber 111 includes a plurality of vertically spaced openings 113 thepurpose of which will become apparent below. A downwardly-biasing tab115 extends into each chamber 111, tab 115 being used to removablysecure magazine 109 within chamber 111 in a snap-lock fashion.

A single magazine 109 is shown in greater detail in FIGS. 11 and 12 (oneassay module 19 having been removed from magazine 109 in the manner tobe described below, magazine 109 being broken away in part to reveal twoadditional assay modules 19 contained therewithin). As can be seen,magazine 109 comprises a generally rectangularly-shaped, open-facedvessel 117. Vessel 117 is internally sectioned so as to define aplurality of vertically stacked compartments 119, each compartment beingfurther subdivided into a pair of horizontally adjacent sections 121 and123, respectively, section 121 being used to hold a single assay module19 (preferably seated therewithin in a nose-in orientation) and section123 being used to receive a piece of the material covering compartment119 once it has been cut away therefrom in the manner described below.An upwardly biasing tab 124 is formed at the rear end of section 121 ofeach compartment 119. Tab 124, which is adapted to engage the bottom ofan assay module 19, is used to restrict longitudinal movement of theassay module within section 121 of compartment 119 until the appropriatetime for its ejection therefrom. An opening 125 is formed in the backwall of each compartment 119 of vessel 117 to permit access to the noseend of the assay module seated therewithin for reasons to be discussedbelow. When magazine 109 is mounted within segment 107, openings 125 ofvessel 117 become aligned with openings 113 of segment 107.

Sheets of material 127-1 and 127-2, which may be a thin foil or otherlike material for preventing moisture or debris from enteringcompartments 119 are adhered to the front and rear surfaces,respectively, of vessel 117. A label 129 having imprinted thereon a barcode or other similar information readable by a bar code reader or thelike is affixed to the bottom of vessel 117 for purposes of identifyingthe specificity of the assay modules contained within vessel 117.

Referring now to FIG. 13, an assay module 19 is shown in greater detail.As can be seen, assay module 19 is an elongated boat-shaped structure131 having an inwardly tapering nose 131-1. An opening 133 is providedinside assay module 19 to provide access to a reagent bearing film 133-1contained therein.

Referring back to FIG. 9, assay module transport assembly 23 can be seento include a scaffolding 141. Scaffolding 141 includes a first pair oflegs 143-1 and 143-2 which extend downwardly through the inside of frame101 and are attached at their bottom ends to a fixed plate 145concentrically disposed within turntable 103. Plate 145 is coupled tothe turntable 103 through a bearing to allow the turntable to rotatewhile plate 145 remains fixed. Scaffolding 141 also includes a secondpair of legs 147-1 and 147-2 which extend downwardly in front of assaymodule supply apparatus 17 and are attached at their bottom ends toframe 36.

Assay module transport assembly 23 also includes an assay module ejectormechanism 151, which is used to eject a desired assay module 19 fromassay module supply apparatus 17 in the manner to be described below. Inorder that its vertical positioning may be adjusted to access assaymodules 19 at various vertical levels within supply apparatus 17,ejector mechanism 151 is mounted on a plate 152, which in turn ismounted on a lead screw 153. Lead screw 153 is coupled to a steppermotor 155 by a belt 157. The operation and direction of motor 155 arecontrolled by the microprocessor. As a result of this elevator-typearrangement, lead screw 153 draws plate 152 and, hence, ejectormechanism 151 either up or down depending on the direction in which leadscrew 153 is turned by motor 155. A guide post 159 is additionallyprovided to prevent plate 152 from rotating due to the turning movementof lead screw 153.

Assay module transport assembly 23 additionally includes an assay modulereceiving platform 161, which is used to receive an assay module 19which has been ejected from assay module supply apparatus 17 by assaymodule ejector mechanism 151. Assay module receiving platform 161 ismounted on a second elevator-type arrangement comprising a plate 162, alead screw 163 on which plate 162 is mounted, and a stepper motor 165 towhich lead screw 163 is coupled by a belt 167. The operation anddirection of motor 165 is also controlled by the microprocessor. A guidepost 169 is additionally provided to prevent plate 162 from rotating aslead screw 163 is turned.

Assay module transport assembly 23 further includes a cutter assembly171 which, as will be seen below, is used to tear away that portion ofsheet of material 127-1 covering a desired compartment 119 of magazine109 and then to tuck the torn strip of material into section 123 ofcompartment 119. Cutter assembly 171 is fixedly mounted on the bottom ofplate 162.

Assay module transport assembly 23 also includes an assay moduletransfer apparatus 173 which, as will be seen below, serves to move anassay module 19 from assay module receiving platform 161 to an assaymodule berth 175 formed on turntable 24.

In addition to assay module supply apparatus 17, assay module transportassembly 23, and turntable 24, a PC board 177 is also shown in FIG. 9.Board 177, which is connected to the microprocessor, includes a pair ofbar code readers 179 for reading the bar codes printed on labels 129,the pair of bar code readers 179 being positioned so that one bar codereader 179 reads the bar codes located on the top row of magazines 109in segment 107 and the other bar code reader 179 reads the bar codeslocated on the bottom row of magazines 109 in segment 107. Board 177also includes a plurality of assay module detectors 181, each detector181 comprising an LED (not shown) whose output is directed at a specificcompartment 119 of magazine 109 and a light detector (not shown)positioned to detect light reflected off the piece of foil 127-1covering the particular compartment. If the piece of material covering acompartment has not been removed, light emitted by the LED will bereflected off the piece of material and detected by the light detector,indicating that an assay module is present within the compartment. If,however, the piece of material has been removed, then the light emittedby the LED will not be reflected off the piece of material covering thecompartment and will not be detected by the light detector, indicatingthat an assay module is not present within the compartment.

Referring now to FIG. 14, there is shown an enlarged front perspectiveview of assay module ejector mechanism 151. As can be seen, assay moduleejector mechanism 151 includes an elongated supporting bracket 183,which is adapted to be mounted on plate 152 (see FIG. 9). A supportingrod 185 extends along the length of bracket 183 and is mounted at theopposite ends thereof. A slider block 187 is mounted on rod 185 forforward and rearward longitudinal sliding movement thereon. A pusher rod189 which, as will be seen below, is used to pierce layer of material127-2 and push an assay module 19 from magazine 109 onto assay modulereceiving platform 161, is mounted on the leading end of slider block187. Slider block 187 is fixedly attached by any suitable means, notshown, to an endless belt 191 which is mounted for movement along a pathdefined by wheels 192, 193, 194, and 195. Belt 191 is driven by astepper motor 197 whose output shaft is fixedly attached to wheel 195.The operation and direction of stepper motor 197 is controlled by themicroprocessor.

Referring now to FIG. 15, there is shown an enlarged top view of assaymodule receiving platform 161. As can be seen, assay module receivingplatform 161 includes a pair of outwardly extending flanges 201-1 and201-2 adapted to receive a screw or the like for securing platform 161to plate 162 (see FIG. 9) and a generally rectangularly shaped trough203 dimensioned to correspond generally to the size and shape of anassay module 19. A pair of inwardly biasing clips 205-1 and 205-2 aremounted on trough 203 to provide a small amount of resistance so that anassay module 19 will not be pushed too far across trough 203 as a resultof the force imparted to the assay module 19 by pusher rod 189 ofejector mechanism 151.

Referring now to FIGS. 16 through 18, there are shown various views ofcutter assembly 171. As can be seen, cutter assembly 171 includes agenerally C-shaped supporting bracket 207, which is adapted to bemounted on the bottom of plate 162 (see FIG. 9) with a pair of screws209-1 and 209-2. A block 211 is slidably mounted inside bracket 207. Oneend of block 211 is shaped to define a cylindrically-shaped, finger-likeprojection or plunger 213. As will be seen below, plunger 213 is used totuck the piece of material from layer 127-1 which has been cut in themanner hereinafter described into section 123 of compartment 119. A rack215, which is engaged by a pinion 217 driven by a stepper motor 219, ismounted along block 211, the rack and pinion arrangement permittingblock 211 to be moved back and forth across bracket 207 in either of thedirections indicated by arrows A in FIG. 16 according to instructionsgiven to motor 219 by the microprocessor.

Cutter assembly 171 also includes a generally C-shaped cutter element221. Cutter element 221 is slidably mounted on block 211 but is biasedtowards plunger 213 by a pair of springs 223-1 and 223-2, which aremounted at one end on a pair of posts 225-1 and 225-2, respectively,fixedly attached to block 211 and at their opposite ends on a pair ofposts 227-1 and 227-2, respectively, fixedly attached to the sides ofcutter element 221. The transverse portion of cutter element 221includes an opening 229 through which plunger 213 of block 211 extendswhen element 221 is moved relative to block 211 in the manner discussedbelow. The transverse portion of cutter element 221 also includes ablade element 231 which, as will hereinafter be discussed, is used tocut that portion of material layer 127-1 covering three sides, forexample, the top, bottom, and right side edges of compartment 119.

Referring now to FIG. 19, there is shown an enlarged perspective view ofassay module transfer mechanism 173. As can be seen, assay moduletransfer mechanism 173 includes a platform 233. Platform 233 isrotatably mounted on a shaft (not shown) which is coupled through a belt(not shown) to a stepper motor 235. The operation and direction ofstepper motor 235 are controlled by the microprocessor. Mounted on topof platform 233 is an assay module loader assembly 237. As can be seenin FIG. 20, assay module loader assembly 237 is virtually identical inconstruction to assay module ejector mechanism 151, the only differencebetween assay module loader assembly 237 and assay module ejectormechanism 151 being that assay module loader assembly 237 does not havea pusher rod 189 mounted on the leading end of slider block 187, butrather, has a loader arm 239, which is fixedly mounted with a screw orsimilar means on the front side of slider block 187. Loader arm 239,which is shown in isolation in FIG. 21, has a pair ofdownwardly-extending tabs 243-1 and 243-2 which are adapted to engagethe nose and rear ends, respectively, of assay module 19 in the mannerto be described below so that assay module 19 may be pulled off assaymodule receiving platform 161 and then pushed onto an assay module berth175 on turntable 24.

When assay module transport apparatus 23 is not in use, assay moduletransfer mechanism 173 is positioned so that platform 233 is rotatedtowards chamber 21 and loader arm 239 is fully extended over turntable24. When actuation of assay module transport assembly 23 is desired,turntable 24 is rotated until a used and no longer needed assay moduleseated on turntable 24 comes into engagement with loader arm 239. Loaderarm 239 then retracts, pulling the used assay module onto platform 233and leaving an empty assay module berth 175 on turntable 24. Next,platform 233 makes an approximately quarter-turn rotation after whichloader arm 239 extends again, ejecting the used assay module fromplatform 233 into a used assay module receptacle (not shown). Loader arm239 then retracts again and platform 233 rotates until loader arm 239 isaligned with assay module receiving platform 161.

Either at the same time, before, or after the above-recited sequence ofevents, turntable 103 rotates, if necessary, so that the magazine 109containing the assay module which it is desired to remove therefrombecomes rotationally aligned with cutter assembly 171. Plate 162 ismoved vertically, if necessary, so that cutter assembly 171 is alignedvertically with the compartment 119 containing the desired assay module.Next, the rack and pinion arrangement of cutter assembly 171 drivesblock 211 (and, hence, cutter element 221) horizontally towards thecompartment 119 containing the desired assay module. This horizontalmovement causes blade element 231 of cutter element 221 to sever threesides, for example, the top, bottom, and right side edges of thatportion of the layer of material 127-1 covering compartment 119;however, further horizontal movement of cutter element 221 towardscompartment 119 is restrained as the remaining surface of the transverseportion of cutter element 221 comes into contact with that portion ofvessel 117 surrounding the compartment 119. Despite the stoppage ofmovement of cutting element 221, block 211 continues to movehorizontally in the direction of compartment 119, causing plunger 213 toextend through opening 229 of cutting element 221 in such a way as topush the now torn piece of the layer of material 127-1 into section 123of compartment 119. The rack and pinion arrangement then reversesdirection causing block 211 and cutting element 221 to retract.

Plate 162 then moves downwardly so that assay module receiving platform161 is aligned vertically with the compartment 119 containing thedesired assay module. Either at the same time, before, or after theabove-recited sequence of events, plate 152 is moved vertically, ifnecessary, so that pusher rod 189 of assay module ejector mechanism 151is vertically aligned with the compartment 119 containing the desiredassay module. Pusher rod 189 is then moved horizontally towards thedesired compartment 119 whereby it passes through the opening 113 on theback of the segment 107, pierces that portion of the layer of material127-2 covering opening 125 of the desired compartment 119, passesthrough opening 125, and pushes the nose end 131-1 of the desired assaymodule 19 out of compartment 119 and onto platform 161. Pusher rod 189is then retracted.

With the desired assay module now on assay module receiving platform161, plate 162 then moves vertically, if necessary, to a waitingposition just below the plane of loader arm 239. Loader arm 239 is thenextended, and plate 162 moves vertically upwardly until the assay moduleon platform 161 engages tabs 243-1 and 243-2 of loader arm 239. Loaderarm 239 then retracts, pulling the assay module off platform 161 andonto platform 233. Platform 233 then rotates so that loader arm 239 isaligned with the empty assay module berth 175 on turntable 24, andloader arm 239 is extended so that the desired assay module is insertedinto the empty berth 175. Turntable 24 then rotates so that the newassay module is no longer aligned with loader arm 239. Loader arm 239 isthen ready to receive another used assay module disposed on turntable 24and the above-described sequence of events may be repeated.

The embodiments of the present invention are intended to be merelyexemplary and those skilled in the art shall be able to make numerousvariations and modifications to it without departing from the spirit ofthe present invention. All such variations and modifications areintended to be within the scope of the present invention as defined inthe appended claims.

What is claimed is:
 1. An automated analytical instrument for use inconducting assays for a component of interest in a fluid sample, saidautomated analytical instrument comprising:a) an assay module supplyunit for holding magazines, said magazines including open-faced vesselswherein a supply of assay modules are disposed at different verticallevels, and each of said open-faced vessels having a layer of materialcovering an open face thereof; b) a testing system for assaying a fluidsample for a component of interest using an assay module; c) an assaymodule transport assembly for transporting an assay module from saidassay module supply unit to said testing system, said assay moduletransport assembly comprisingi) an assay module receiving platformdisposed next to said assay module supply unit for receiving an assaymodule removed from said assay module supply unit, ii) an assay moduleejector mechanism for pushing an assay module from said assay modulesupply unit onto said assay module receiving platform, iii) an assaymodule transfer mechanism for transferring an assay module from saidassay module receiving platform to said testing system; iv) a cutterassembly for cutting said layer of material so as to permit access tosaid assay module disposed within said open-faced vessel, said cutterassembly being carried by said assay module receiving platform; v) meansfor moving said assay module receiving platform and said cutter assemblyvertically and means for moving said assay module ejector mechanismvertically whereby said assay modules disposed at different verticallevels in said assay module supply unit may be accessed; and d) amicroprocessor for controlling the operation of said automatedanalytical instrument.
 2. The automated analytical instrument as definedin claim 1 wherein said assay module ejector mechanism comprises apusher rod and an arrangement for slidably moving said pusher rod. 3.The automated analytical instrument as defined in claim 2 wherein saidarrangement for slidably moving said pusher rod includes a motor, anendless belt driven by said motor, and a slider block attached to saidendless belt and to said pusher rod.
 4. The automated analyticalinstrument as defined in claim 1 wherein said cutter assembly comprisesa cutting element and an arrangement for slidably moving said cuttingelement for engagement with the layer of material.
 5. The automatedanalytical instrument as defined in claim 4 wherein said arrangement forslidably moving said cutting element for engagement with the layer ofmaterial comprisesa) a block, said cutting element being mounted on saidblock; b) a rack mounted on said block; c) a motor; and d) a pinionmounted on said motor and engaged with said rack for slidably movingsaid block.
 6. The automated analytical instrument as defined in claim 1wherein said cutter assembly comprises a cutting element for cutting thelayer of material and a plunger for pushing a cut piece of material intothe open-faced vessel out of the way of the assay module disposedtherewithin.
 7. The automated analytical instrument as defined in claim1 wherein said assay module transfer mechanism comprises a rotatableplatform and a retractable arm engageable with an assay module forpulling an assay module from said assay module receiving platform ontosaid rotatable platform and for pushing the assay module from saidrotatable platform into said testing system.
 8. An assay moduletransport assembly for use in transporting an assay module from an assaymodule supply unit to a testing system within an automated analyticalinstrument, said assay module transport assembly comprising:a) an assaymodule receiving platform disposed next to the assay module supply unit;b) an assay module ejector mechanism for pushing an assay module fromthe assay module supply unit onto said assay module receiving platform;c) an assay module transfer mechanism for transferring an assay modulefrom said assay module receiving platform to the testing system; d) acutter assembly for cutting a layer of material which covers anopen-face of an open-faced vessel of a magazine in which an assay moduleis disposed, said cutter assembly being carried by said assay modulereceiving platform; and e) means for moving said assay module receivingplatform and said cutter assembly vertically and means for moving saidassay module ejector mechanism vertically whereby assay modules disposedat different vertical levels in the assay module supply unit may beaccessed.
 9. The assay module transport assembly as defined in claim 8wherein said assay module transfer mechanism comprises means for pullingan assay module off said assay module receiving platform and for pushingthe assay module into the testing system.